Nitrox fills

[jasondbaker]

I have an update on this thread. The question is: can you put air in a cylinder marked with a NITROX sticker? Corey with PSI (Professional Scuba Inspectors, Inc.) was kind enough to respond to this question.

Corey:

...I want to make sure I am clear in saying you must not
fill a cylinder with a gas other then what the cylinder is marked for. Cylinders with no markings are generally assumed to contain non-hazardous air. Air being define as 21% O2 & 78% N2 with less then 1% other gas. So, in the case you described, a Nitrox cylinder must be drained completely, given a complete visual inspection (PSI policy), and any Nitrox markings (stickers) removed prior to refilling it with air.

The specific legal citation for removing the stickers comes from the DOT and is stated in Code of Federal Regulations Title 49, Subtitle B, Chapter 1, Part 172, Subparts D & E.

Line 172.303 (a) of D states "No Person may offer for transportation or transport a package which is marked with the proper shipping name or identification number of a hazardous material unless the package contains the identified hazardous material..."

Line 172.401(b) of E states "No person may offer for transportation and no carrier may transport a package bearing any marking or label which by its color, design, or shape could be confused with or conflict with a label prescribed by this part."

You may read these citations in full content at:



DOT considers any gas with greater then 21% O2 to be an oxidizer and labeled as such. The Nitrox label indicates this and by putting air in a cylinder marked for Nitrox, you are in violation of several DOT regulations.